DIGITAL EDITION

Winding Up Productivity with Roll-to-Roll Screen-Printing Technology

(July 2008) posted on Thu Jul 03, 2008

Advanced digital control systems, improved engineering, and better material-handling technology characterize the latest generation of automated screen-printing systems for wide-format web substrates. Learn about the ease of operation, precision, and high throughput they can deliver in industrial and electronics printing environments.

The latest generation of roll-to-roll screen-printing systems marks a significant evolutionary step in the press technology that has dominated since the early 1900s. Now, the incorporation of more sophisticated electronic controls reduces the need for time-consuming manual adjustments that typify earlier and less sophisticated equipment. In this discussion, we will consider how state-of-the-art electronic controls and software integration are changing the capabilities of roll-to-roll screen-printing systems, including both flatbed models (Figure 1) and cylinder systems (Figure 2).

The underlying electronics and software engineering that now have bearing on screen-printing technology are cut from the same cloth as the electronic controls we now see in a wide swath of industrial equipment. At the core are programmable logic controllers (PLCs)—computers geared to provide stability in real-world manufacturing conditions and able to handle multiple inputs and outputs. PLCs, originally developed for the automotive industry, are now programmed with more sophisticated instructions than when they were originally introduced, enabling expert programmers to fine tune industrial controls to an unprecedented extent. This includes today’s PLCs that can fully automate the steps in roll-to-roll screen printing.

Job setup and tool-free changeovers

Adjustments to the screen clamps, as well as squeegee and floodbar pressures, can now be achieved with touchscreens operating pneumatic controls via the system’s PLC. This eliminates a good deal of time that had previously been spent by operators making mechanical adjustments to balance these components for each job. On today’s roll-to-roll presses, no tools are required to make these adjustments—they are all done electronically and with greater precision and repeatability than what human operators can typically muster. If and when fault conditions arise, they can also be corrected with a few keystrokes.

Going from a manually sheet-fed printing process to an automated web process can speed throughput by 50% or more. The actual speed improvement varies and is dependent on the size of the job, among other factors.

Once a skilled operator has set up all the required job parameters for a particular application—web speed, web transport settings, squeegee angle, screen height, dryer settings, etc.—the PLC will automatically store all these parameters. For repeat runs of the same job, a far less skilled operator is able to quickly initiate and set up the system by recalling those parameters.